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Alloy 625 is a nickel-chromium-molybdenum-niobium alloy with exceptional corrosion resistance and fatigue resistance. The alloy has a high chromium and molybdenum content, and is primarily used in the oil and gas, energy, and environmental technology sectors.
The material is available in the softened and annealed condition (Grade 1), with an annealing temperature of 950 to 1050°C (1742 to 1922°F), commonly used in wet corrosive environments and has been TÜV certified for pressure vessels operating at temperatures between -196 to 450°C (-335 to 842°F).
For high temperature environments exceeding 600°C, the solution annealed condition (Grade 2) with an annealing temperature of 1080 to 1160°C (1976 to 2120°F) is recommended. Heat treatment can be used to increase the strength of Alloy 625.
Chemical composition overview (%):
|
|
Ni |
Cr |
Fe |
C |
Mn |
Si |
W |
Mo |
Co |
V |
P |
S |
|
Max. |
51 |
15 |
4 |
|
|
|
3 |
15 |
|
|
|
|
|
Min. |
63 |
16.5 |
7 |
0.01 |
1 |
0.08 |
4.5 |
17 |
2.5 |
0.3 |
0.02 |
0.01 |
Material Properties:
● Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking
● Virtually immune to stress corrosion cracking caused by chlorides
● Good corrosion resistance to inorganic acids (such as nitric, phosphoric, sulfuric, and hydrochloric acids)
● Good resistance to alkaline solutions
● High mechanical strength
● High creep rupture strength (at temperatures above 600°C)
● Good resistance to various types of gas-phase corrosion (especially chloridation)
Corrosion Resistance:
To achieve the best corrosion resistance, the material must be in the correct metallurgical condition and have a pure structure. In the softened and annealed condition (Grade 1), the alloy exhibits excellent corrosion resistance in various corrosive media:
● Excellent resistance to pitting and crevice corrosion in chloride-containing environments
● Virtually immune to stress corrosion cracking caused by chlorides
● Excellent corrosion resistance to inorganic acids such as nitric, phosphoric, sulfuric, and hydrochloric acids, as well as high-concentration alkalis and organic acids, in both reducing and oxidizing environments
● Excellent corrosion resistance in high-temperature environments and seawater immersion
● High resistance to intergranular corrosion after welding and heat treatment
● Excellent resistance to erosion-corrosion
● In the solution annealed condition (Grade 2), the alloy has good resistance to various corrosive gases:
● Good resistance to carburization and scaling under static and cyclic conditions
● Corrosion resistance in nitriding environments
● Resistance to halogen and hydrochloric acid-containing gases
Material Applications:
● Equipment for super-phosphoric acid production
● Radioactive waste treatment plants
● Production pipelines and tubing liners in oil production
● Marine industry and components exposed to seawater
● Shipbuilding industry for seawater piping
● Stress-corrosion-resistant expansion joints
● Furnace linings
● Flare tips in refineries and offshore platforms
● Heat exchangers and expansion joints for hot waste gases
Available Products:
Shanghai COCESS Special Alloys Co., Ltd. can produce and supply Inconel 625 in the form of bars, plates, strips, pipes, capillary tubes, fittings, flanges, forgings, fasteners, and welding materials. Please contact us for more product details.
